Apparatus for atomizing molten metal

ABSTRACT

Apparatus for atomizing molten steel or the like into powder in which the molten steel is degassed and then poured in a vertical stream into an atomizing chamber. The metal in the stream is atomized by directing atomizing fluid at the stream.

United States Patent 1 92,4 3

Lightner [451 Sept. 19, 1972 [54] APPARATUS FOR ATOMIZING 1,601,897 10/ 1926 Wiley et a1 ..18/2.5 R MOLTEN METAL 3,588,951 6/1971 Hegmann ..l8/2.5R 72 Inventor: Max w. Lightner, Mount Lebanon 'gg? g 5 32 9? gg i Township Allegheny County Pa ,5 1 /1 0 Ian 3,428,718 2/1969 Helm et al. ..264/12 X 73 A U '1 S t sslgnee m ed 8 FOREIGN PATENTS OR APPLICATIONS [2 1 1970 1,958,610 6/1970 Germany ..264/12 [21] Appl. No.: 85,044 181,610 4/1955 Austria ..18/2.5 R 1,361,521 4/1964 France ..l8/2.5 R [52] US. Cl. ..425/7, 266/34 V Primary Spencer Overholser [51] Int. Cl. ..B22d 23/08 Assistant Exammer-Ben D. Tobor Fleld of Search 5 R, 2, 7; Au0rney Martin Carroll [57] ABSTRACT [56] References Cited Apparatus for atom1z1ng molten steel or the like into UNITED STATES PATENTS powder in which the molten steel is degassed and then poured in a vertical stream into an atomizing chamber. The metal in the stream is atomized by y d' ti t H d tr 3,340,334 9/1967 Feldman et al ..l8/2.5 R x a omlzmg a e S eam 2,159,433 5/1939 Ervin ..l8/2.5 R X 8 Claims, 1 Drawing Figure 7'0 Vacuum Pump Inert Gas PATENTEIJ E 1 9 I972 3.692.443

To Vacuum Pump Inert Gas INVENTOR. MAX W. LIGHT/V55 m/QM A I I orney APPARATUS FOR ATOMIZING MOLTEN METAL This invention relates to apparatus for atomizing molten metal, particularly molten steel, into powder. It is common to make both pre-alloyed and un-alloyed powder by directing high speed jets of high pressure fluids on a molten metal stream to atomize it.

A major problem associated with this atomization is flaring of the liquid metal stream on exit from the pouring orifice. The stream spreads laterally and becomes ragged, making it difficult to focus the high speed jets on the stream. This results in a certain portion of the metal avoiding the jets and falling to the bottom of the collecting chamber in the form of metallic globules rather than powder.

It is therefore an object of my invention to provide apparatus for atomizing molten metal which increases the over-all quality of the product.

Another object is to provide such apparatus which atomizes a larger percentage of the molten metal than prior apparatus.

These and other objects will be more apparent after referring to the following specification and attached drawing, in which:

The single FIGURE is a vertical section of the apparatus of my invention.

Referring more particularly to the drawings, reference numeral 2 indicates a vacuum degassing chamber having a bottom pouring spout 4 and a stopper 6 associated therewith. A removable top 8 covers the top of the chamber and has an exhaust pipe 10 connected to a vacuum pump (not shown). A sight tube 12 and a charging tube 14 are connected to the top 8. A charging box 16 is connected to the tube 14 for alloy additions when desired. An inlet port 18 in top 8 has a seal plate 20 associated therewith for closing the port 18 during evacuation. Molten metal is poured into chamber 2 through port 18 from a ladle 22 adapted to sit on top of the lid 8 over port 18. The ladle 22 has a bottom pouring spout 24 and a stopper 26 associated therewith. A nozzle pipe 28 extends downwardly from chamber 2 around spout 4 and is provided with an inert gas pipe 30. The parts so far described are conventional and are described in greater detail in Hornak et al US. Pat. No. 3,125,440 dated Mar. 17, 1964. It will be understood that other types of degassing equipment may be used in place of. that described.

According to my invention I provide an atomization chamber 32 provided with a molten metal inlet orifice 34 which is connected to pipe 28. A plate 36 closes the opening through pipe 28 during evacuation. A sight tube 38 is provided at the top of chamber 32. Circular fluid headers 40 and 42 are centrally located in chamber 32 below orifice 34 and are connected by pipes 44 and 46, respectively, to an atomizing fluid source, not shown. The headers 40 and 42 are provided with ports 4UP and 42P which are all directed downwardly and inwardly so that the fluid will intersect generally in the molten metal stream S at a single point. Exhaust pipes 48 and 50 connected to a suitable fluid disposal system are provided in the wall of chamber 32. A powder bin 52 is located beneath chamber 32 and is separated from it by a gate valve 54. A gate valve 56 at the bottom of bin 52 controls flow of powder therefrom.

In operation, with the plates 20 and 36 in place the chamber 2 is evacuated to say microns of mercury. The ladle 22 is then placed in position and molten metal, such as molten steel M, is then poured through spout 24 and fuses plate 20 and flows into chamber 2. Gases dissolved in the steel are evolved and escape through pipe 10. After the chamber 2 is filled to the desired level and any additions which may have been made are fused, the stopper 6 is opened to permit flow of the molten steel in a stream into the chamber 32. Because the metal is degassed the stream S does not flare, but is smooth and compact. The molten metal passes axially through headers 40 and 42 and a high pressure atomization fluid from the headers are directed at the liquid metal stream S to atomize the metal into powder, which is collected in bin 52. If a gaseous atomization fluid is used, exhaust pipes 48 and 50 will be connected to a gas disposal system. If a liquid atomization fluid is used, exhaust pipe 48 will serve as a liquid overflow port. The powder formed is removed from bin 52 from time to time by closing valve 54 and opening valve 56. After removal of the powder the valve 56 is closed and the valve 54 opened. This procedure is repeated until the molten metal is exhausted.

While one embodiment of my invention has been shown and described, it will be apparent that other adaptations and modifications may be made without departing from the scope of the following claims.

Iclaim:

1. Apparatus for atomizing molten metal comprising means for degassing the molten metal including a vacuum degassing container, an outlet from said container for forming a smooth and compact stream of molten metal, an atomizing chamber separate from said degassing means and said container, means for delivering the degassed molten metal stream from said outlet to said atomizing chamber, and means in said chamber for directing atomizing fluid at said stream to atomize the molten metal.

2. Apparatus according to claim 1 in which said means for directing atomizing fluid includes a circular header surrounding said stream, and a plurality of ports in said header directed inwardly away from the direction of approach of said stream to generally intersect in said stream.

3. Apparatus according to claim 1 in which said degassing means is a degassing chamber located above said atomizing chamber, and said means for delivering the degassed molten metal is a vertical connection between said chambers whereby a substantially vertical stream of degassed molten metal is provided.

4. Apparatus according to claim 3 in which said means for directing atomizing fluid includes a circular header surrounding said stream, and a plurality of ports in said header directed inwardly downwardly to generally intersect in said stream.

5. Apparatus according to claim 4 in which said means for directing atomizing fluid includes a second circular header surrounding said stream below said first named header, and having a larger diameter than said first named header, a plurality of ports in said second header directed inwardly and downwardly to generally intersect in substantially the same horizontal plane as the first named ports.

bin.

8. Apparatus according to claim 1 in which said means for directing atomizing fluid includes a plurality of atomizing gas ports, and means for delivering high pressure atomizing gas to said gas ports. 

1. Apparatus for atomizing molten metal comprising means for degassing the molten metal including a vacuum degassing container, an outlet from said container for forming a smooth and compact stream of molten metal, an atomizing chamber separate from said degassing means and said container, means for delivering the degassed molten metal stream from said outlet to said atomizing chamber, and means in said chamber for directing atomizing fluid at said stream to atomize the molten metal.
 2. Apparatus according to claim 1 in which said means for directing atomizing fluid includes a circular header surrounding said stream, and a plurality of ports in said header directed inwardly away from the direction of approach of said stream to generally intersect in said stream.
 3. Apparatus according to claim 1 in which said degassing means is a degassing chamber located above said atomizing chamber, and said means for delivering the degassed molten metal is a vertical connection between said chambers whereby a substantially vertical stream of degassed molten metal is provided.
 4. Apparatus according to claim 3 in which said means for directing atomizing fluid includes a circular header surrounding said stream, and a plurality of ports in said header directed inwardly downwardly to generally intersect in said stream.
 5. Apparatus according to claim 4 in which said means for directing atomizing fluid includes a second circular header surrounding said stream below said first named header, and having a larger diameter than said first named header, a plurality of ports in said second header directed inwardly and downwardly to generally intersect in substantially the same horizontal plane as the first named ports.
 6. Apparatus according to claim 5 including means for exhausting said atomizing fluid from said atomizing chamber.
 7. Apparatus according to claim 6 including a bin at the lower end of said atomizing chamber for receiving the atomized metal, and top and bottom valves for controlling flow of said atomized metal to and from said bin.
 8. Apparatus according to claim 1 in which said means for directing atomizing flUid includes a plurality of atomizing gas ports, and means for delivering high pressure atomizing gas to said gas ports. 